what could cause my avg mpg to drop .3 in 2 miles?? dealer screwing me over?
 

so I picked up my car from the dealer after being there for a week for some issues I had with my body kit and also to get my five ad wheels installed, when I got the car back it had 2.1 extra miles on it wich is understandable considering they probably had to drive it after wheels were put on. my question is my avg mpg whet from 33.2 to 32.9, .3 diffrence, that posted a red flag in my book, I talked to the manager of the servie department regarding the issue, and he said it was from the car idoling for a long period of time while it was there, i replied why would my car be idoling when wheels and tires are installed? he had not definate answer, needless to say i had a few choice words for him. so my question is, is this a logical explanation on the dealers part? or did someone just take my car out for a magor joy ride.my car had 1580 miles on it and I drove it back home 20 miles and the avg mpg meter did not move at all.

Always the dealer's fault, eh? Jeez, just drive it around for a few days and see what happens.

I think you're panicking for nothing. It's just 2.1 miles. I'd be concerned if you valeted the car and it had that many extra miles.

Anyway, your average mpg will vary! It's just 0.3 difference! It's not that much. If you give the car a little extra gas every now and then, it'll do that. Especially if the tank was close to full, it'll vary your avg. mpg. I think you're freaking out about nothing buddy.

Take a chill pill and relax. It's Labor Day weekend.

You're expecting too much from your dealership. It's likely they drove your car to lunch and on the way there and back tried a little drifting.

probably just idling. getting 0mpg will cause it to drop rather quickly.

You lost me after

The average would also drop if there are a lot of stoplights near the dealership. Traveling a short distance in stop-and-go traffic would bring it down.

It also depends on when you reset the mileage. If you had just filled up and reset the MPG gauge (I always reset after a fill-up) Then small bouts of less than average gas mileage will quickly lower the average. For example, I usually get around 29 MPG on average for my commute. I filled up before my commute and was reading 30.x MPG afterwards. The next day I was in a traffic jam on my way to work and in two or three miles the avg. was reading 27.x. It bounced back up by the end of the commute and by the end of the tank, I was right at my normal average.

did they swap your tpms over to the new wheels?

I think you should be driving a prius,

I got 8 mpg when i did about 4 doughnuts in the parking lot earlier today:bonk:

Jesus man, a car's average mileage drops significantly when it's just sitting around idling, or being parked, etc. You lost almost nothing (.3). If it dropped 15MPG, then I'd be concerned.

Chill out fellas. Everyone is currently 'anal' about their cars at the moment. I agree with the statements above it's probably because it was idling which most shops do.

ofcourse they did a little post service testing, and no they didnt warm it up..LOL

yes they did

ok, just making shure i wasnt crazy, look if all of you had your car since june 14th and its been at the dealer for about 3 weeks of that time because they cant install a simple body kit you would be as mad as i am too,lol. thanks for the imput everyone.

Seriously why care so much? If you want a better mpg avg get a Nissan leaf or a Prius. My avg is 23.9 but I'm not complaining. This car was meant to be driven and have fun in, not economical.

I would say another set of wheels will definitely change your mpg. BUT man, 0.3 is way below a normal variation. Consider it is nothing. I've been driving on the same stretch of 100-mile hiway with the same car for years. I see about 2 mpg variations. If there is weather or passenger, or mood, there will be even larger variations.

:laughabove: @ "mood"

The average MPG readout is wrong anyway, why care?

I get it and understand your concern.
If the average dropped by 0.3mpg in just 2.1 miles they must have thrashed the guts out of it.

The problem is that you've lost faith with the dealer and with good reason by the sounds of it.

That's an unwarranted assumption unless we know how many miles the average is based on -- which the OP hasn't mentioned yet.

Ever heard of idling...christ...some people on this site :lol:

If the OP had never reset the average and the 33.2 mpg is the average over 1580 miles, that means the dealer got average of 4.2 mpg over the 2.1 miles in order to make the average drop to 32.9 mpg by 1582 miles.

^^ Yes, and if the average was over 50 miles, 10 minutes of idling would drop it the same amount.

So, OP which is it? Was the average based on 1580 miles or the 30 miles you drove since your last fill? lol

Correct this is based off of the 1580

I have never reset it the entire life of the car.

If you had 32.9 over 1600 miles you must live in an M. C. Escher everywhere is down hill world.

Jeez, give the car some throttle every once in a while ...

Anyway, I wouldn't trust the MPG gauge much. If Sigh-on-Rice's math is correct, there's no way they could have gotten 4.2 MPG while driving 2.1 miles. I guess they could have put it on a jack stand, put a brick on the throttle and went out to lunch if that's any consolation.

Whats with all this "why care" attitude; 3 months ago the big issue was 4miles or 7miles upon delivery.

Why did they need to drive it anything near a mile? Torque the lugs and she's good. Sorry to hear about your dealership issues, unfortunately its nothing new.

he had new wheels put on. Not a simple rotation of the stock wheels. They probably had it idling on the lift while they checked clearances. They likely had to drive it to load the suspension all while stopping and checking chalk marks on the tires to check for rubs, etc. Nothing unusual at all in any of that.

So if it normally takes 16.5 miles to burn the 1/2 gallon of missing fuel, how long do you think it would have been left idling on the hoist to do it?
2, 4, 8 hours?

No idea. But we are talking about a .3 difference in the reading. As someone pointed out earlier, that's likely well below the error bar of the MPG gauge itself.

Lots of different answers to avoid the obvious one.

The obvious answer is they hooned it. But really, to get 4.3 MPG over 2 miles is likely not really possible. Like I said, they could have simply been malicious and put a brick on the pedal with the car in neutral.

I wouldn't rely on the onboard display over .3 mpg. The more I drive my BRZ the more accurate it becomes. Also, maybe your AC was on which resulted in the decreased mpg. So many possibilities.

Average MPG falls (usually a hell of a lot more than .3mpg) when vehicles are idling, it's a fact and it's not bullshit. They had your vehicle idling for the sake of QC'ing (quality control) it before they gave it back to you; you said it had been there for a week, imagine for a second that when you got it back something completely unrelated and likely coincidental decided to be defective. What's the first thing you do? You run back to the dealership with a case of the "ever since ya's" even though what they did had nothing to do with what had recently gone wrong. We let technicians check the vehicle over while the vehicle is OFF, KOEF (Key on engine off; IE. Accessory mode) and running for the sake of identifying any additional issues so that WE can cover OUR asses and let YOU the customer know what's wrong with YOUR vehicle. You should have been thanking him that he went the extra mile and did that for you, not giving him a few "choice words". He probably didn't want to tell you this because in my experience once a customer is that angry over something so illogical they're seeing black and white, there's no room for rationale. Try not yelling/swearing at your service advisor when you're concerned about something and approach him with a level head/open mind, you'd be surprised what you can learn (it's not as though we don't see your car and many others multiple times a day, all day, every day).

The advisor is the person that generally oversees your repairs, gives the work to the technicians and wants the work being done to vehicles expidited as quickly as possible (he's a middle man in a sense). That's how they get paid, and we also get paid based on customer satisfaction; so when something so illogical is thrown back in our faces and we really can't calm you down you're essentially taking money out of our pocket for a misunderstanding. They aren't the ones doing the work to the car, they have no control over how long it takes or if the technician runs into any problems, and if you had a fraction of an idea how bloody stressful it is dealing with customers like you all day that want take your anger and blast it at the middle man; you probably would never yell at another advisor again. I literally HATE customers like you. You look at us and talk down to us worse than most people talk to house pets; we're people too god damnit give us SOME respect. PS. you're car is new, think about it. What work could we possibly upsell you that you wouldn't need that wouldn't be covered by warranty? You think we can submit non-defective parts to whatever Franchise we work for's warranty department? You think that engineers that have a hell of a lot of indepth product knowledge could be fooled by a sabotaged part? You think we want you to come back to the dealership a week or two later after we just let your car go, like that wouldn't hurt our dealerships public image?

Use your brain for more than rage. Maybe you won't get so angry over stupid misunderstandings.


/endrant

P.S. not all of this is directed at you, some of it is a lot of what I wish I could say to customers without losing my job. Don't know why people think dealers are out to give them the sandpaper dildo, when all most of us (I can't speak for everyone) are trying to do is fix your car, make you happy, and provide our shop with a longtime happy customer.

Actually I can get it to drop more than that in 0.0 miles. For all we know it dropped .6 and they drove it 2.1 miles gently to bring it back up to just .3 less.

Assumptions never make for good evidence.

As for worrying about this, I agree with the others.

lol I said that wasn't worth worrying about too if you remember :)

Yup, don't use AVG MPG data for anything other than a quick check of MPG. Don't backwards engineer an issue due to a gross averaging calculation of MPG. btdt, with the Nissan 350's mpg calculator and the 06 Outback's.

Eric G

Quality Control. Manufacturers require you to road test after EVERY repair. And if I just had wheels put on I would rather my car be road tested for 2 miles than for me to come back because I'm getting a vibration at highway speed.

I realize he had his wheels put back on but a lot can happen in 2 miles, its excessive... besides nothing should go wrong when it comes to torquing wheels to spec.

They probably gave the car a quick rompin'